/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package org.dom4j.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.dom4j.Attribute;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.QName;
import org.dom4j.tree.BackedList;
import org.dom4j.tree.DefaultElement;

/**
 * <p> <code>IndexedElement</code> is an implementation of {@link Element}which
 * maintains an index of the attributes and elements it contains to optimise
 * lookups via name. </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.2 $
 */
public class IndexedElement extends DefaultElement
{
   /** Lazily constructed index for elements */
   private Map elementIndex;

   /** Lazily constructed index for attributes */
   private Map attributeIndex;

   public IndexedElement(String name)
   {
      super(name);
   }

   public IndexedElement(QName qname)
   {
      super(qname);
   }

   public IndexedElement(QName qname, int attributeCount)
   {
      super(qname, attributeCount);
   }

   public Attribute attribute(String name)
   {
      return (Attribute) attributeIndex().get(name);
   }

   public Attribute attribute(QName qName)
   {
      return (Attribute) attributeIndex().get(qName);
   }

   public Element element(String name)
   {
      return asElement(elementIndex().get(name));
   }

   public Element element(QName qName)
   {
      return asElement(elementIndex().get(qName));
   }

   public List elements(String name)
   {
      return asElementList(elementIndex().get(name));
   }

   public List elements(QName qName)
   {
      return asElementList(elementIndex().get(qName));
   }

   // Implementation methods
   // -------------------------------------------------------------------------
   protected Element asElement(Object object)
   {
      if(object instanceof Element)
      {
         return (Element) object;
      }
      else if(object != null)
      {
         List list = (List) object;

         if(list.size() >= 1)
         {
            return (Element) list.get(0);
         }
      }

      return null;
   }

   protected List asElementList(Object object)
   {
      if(object instanceof Element)
      {
         return createSingleResultList(object);
      }
      else if(object != null)
      {
         List list = (List) object;
         BackedList answer = createResultList();

         for(int i = 0, size = list.size(); i < size; i++)
         {
            answer.addLocal(list.get(i));
         }

         return answer;
      }

      return createEmptyList();
   }

   /**
    * DOCUMENT ME!
    * 
    * @param object DOCUMENT ME!
    * 
    * @return DOCUMENT ME!
    * 
    * @deprecated WILL BE REMOVED IN dom4j-1.6 !!
    */
   protected Iterator asElementIterator(Object object)
   {
      return asElementList(object).iterator();
   }

   // #### could we override the add(Element) remove(Element methods?
   protected void addNode(Node node)
   {
      super.addNode(node);

      if((elementIndex != null) && node instanceof Element)
      {
         addToElementIndex((Element) node);
      }
      else if((attributeIndex != null) && node instanceof Attribute)
      {
         addToAttributeIndex((Attribute) node);
      }
   }

   protected boolean removeNode(Node node)
   {
      if(super.removeNode(node))
      {
         if((elementIndex != null) && node instanceof Element)
         {
            removeFromElementIndex((Element) node);
         }
         else if((attributeIndex != null) && node instanceof Attribute)
         {
            removeFromAttributeIndex((Attribute) node);
         }

         return true;
      }

      return false;
   }

   protected Map attributeIndex()
   {
      if(attributeIndex == null)
      {
         attributeIndex = createAttributeIndex();

         for(Iterator iter = attributeIterator(); iter.hasNext();)
         {
            addToAttributeIndex((Attribute) iter.next());
         }
      }

      return attributeIndex;
   }

   protected Map elementIndex()
   {
      if(elementIndex == null)
      {
         elementIndex = createElementIndex();

         for(Iterator iter = elementIterator(); iter.hasNext();)
         {
            addToElementIndex((Element) iter.next());
         }
      }

      return elementIndex;
   }

   /**
    * A Factory Method to create the index for attributes
    * 
    * @return DOCUMENT ME!
    */
   protected Map createAttributeIndex()
   {
      Map answer = createIndex();

      return answer;
   }

   /**
    * A Factory Method to create the index for elements
    * 
    * @return DOCUMENT ME!
    */
   protected Map createElementIndex()
   {
      Map answer = createIndex();

      return answer;
   }

   protected void addToElementIndex(Element element)
   {
      QName qName = element.getQName();
      String name = qName.getName();
      addToElementIndex(qName, element);
      addToElementIndex(name, element);
   }

   protected void addToElementIndex(Object key, Element value)
   {
      Object oldValue = elementIndex.get(key);

      if(oldValue == null)
      {
         elementIndex.put(key, value);
      }
      else
      {
         if(oldValue instanceof List)
         {
            List list = (List) oldValue;
            list.add(value);
         }
         else
         {
            List list = createList();
            list.add(oldValue);
            list.add(value);
            elementIndex.put(key, list);
         }
      }
   }

   protected void removeFromElementIndex(Element element)
   {
      QName qName = element.getQName();
      String name = qName.getName();
      removeFromElementIndex(qName, element);
      removeFromElementIndex(name, element);
   }

   protected void removeFromElementIndex(Object key, Element value)
   {
      Object oldValue = elementIndex.get(key);

      if(oldValue instanceof List)
      {
         List list = (List) oldValue;
         list.remove(value);
      }
      else
      {
         elementIndex.remove(key);
      }
   }

   protected void addToAttributeIndex(Attribute attribute)
   {
      QName qName = attribute.getQName();
      String name = qName.getName();
      addToAttributeIndex(qName, attribute);
      addToAttributeIndex(name, attribute);
   }

   protected void addToAttributeIndex(Object key, Attribute value)
   {
      Object oldValue = attributeIndex.get(key);

      if(oldValue != null)
      {
         attributeIndex.put(key, value);
      }
   }

   protected void removeFromAttributeIndex(Attribute attribute)
   {
      QName qName = attribute.getQName();
      String name = qName.getName();
      removeFromAttributeIndex(qName, attribute);
      removeFromAttributeIndex(name, attribute);
   }

   protected void removeFromAttributeIndex(Object key, Attribute value)
   {
      Object oldValue = attributeIndex.get(key);

      if((oldValue != null) && oldValue.equals(value))
      {
         attributeIndex.remove(key);
      }
   }

   /**
    * Factory method to return a new map implementation for indices
    * 
    * @return DOCUMENT ME!
    */
   protected Map createIndex()
   {
      return new HashMap();
   }

   /**
    * Factory method to return a list implementation for indices
    * 
    * @return DOCUMENT ME!
    */
   protected List createList()
   {
      return new ArrayList();
   }
}

/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived
 * from this Software without prior written permission of MetaStuff, Ltd. For
 * written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may
 * "DOM4J" appear in their names without prior written permission of MetaStuff,
 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
